#include <stdio.h>
int main (void)
{
	int n,x;
	printf ("Please input a number:");
	scanf("%d",&n);
	x = n/10;
	switch (x)
	{
		case 9:case 10:
			printf ("A");
			break;
		case 8:
			printf ("B");
			break;
		case 7:
			printf ("C");
			break;
		case 6:
			printf ("D");
			break;
		default:
			printf ("E");
			break;
	}
	return 0;
}
